49 Andromedae

This article is about A Andromedae and is not to be confused with α Andromedae.

49 Andromedae is a star in the constellation Andromeda.^[1] 49 Andromedae is the Flamsteed designation (abbreviated 49 And),^[9] though it also bears the Bayer designation A Andromedae.^[8] It is visible to the naked eye under good viewing conditions with an apparent visual magnitude of 5.269.^[3] The distance to 49 Andromedae, as determined from its annual parallax shift of 9.8 mas,^[2] is around 333 light-years. It is drifting closer to the Sun with a heliocentric radial velocity of −11.5 km/s.^[3]

49 Andromedae

Location of 49 Andromedae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Andromeda[1]
Right ascension	01h 30m 06.10151s[2]
Declination	+47° 00′ 26.1811″[2]
Apparent magnitude (V)	5.269[3]
Characteristics
Evolutionary stage	red clump[4]
Spectral type	K0 III[5]
B−V color index	0.993[3]
Astrometry
Radial velocity (Rv)	−11.48[3] km/s
Proper motion (μ)	RA: −0.950 mas/yr[2] Dec.: −42.638 mas/yr[2]
Parallax (π)	9.7947±0.1166 mas[2]
Distance	333 ± 4 ly (102 ± 1 pc)
Absolute magnitude (MV)	0.50[1]
Details
Mass	2.07[3] M☉
Radius	11[6] R☉
Luminosity	70.8[3] L☉
Surface gravity (log g)	2.30[4] cgs
Temperature	4,879±106[3] K
Metallicity [Fe/H]	+0.020±0.04[4] dex
Rotational velocity (v sin i)	2.0[7] km/s
Age	1.75[3] Gyr
Other designations
A And[8], 49 And, BD+46°370, HD 9057, HIP 6999, HR 430, SAO 37275, PPM 44057, GSC 03282-02272[9]
Database references
SIMBAD	data

With an estimated age of 1.75 Gyr^[3] years, this is an aging red-clump^[4] giant star with a stellar classification of K0 III,^[5] indicating it is generating energy by helium fusion at its core. The spectrum displays "slightly strong" absorption lines of cyanogen (CN).^[5] It has 2.07^[3] times the mass of the Sun and has expanded to 11^[6] times the Sun's radius. The star is radiating 71^[3] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,879 K.^[3] It is spinning with a projected rotational velocity of 2 km/s.^[7]

This was one of the stars historically known as Adhil, from Arabic að-ðayl "the train [of a garment]", a name now applied to ξ Andromedae.^[10] In a 1971 NASA technical memorandum listing star names, 49 Andromedae was listed as Thail, likely derived from the same Arabic name.^[11]